From the ALSA wiki
ALSA shortcomings and issues
No software is perfect, and few pieces of software are ever completed, though many are finished.
Follows a list of stuff known to be problematic with ALSA; some of these things may not be problems in the eyes of the developers, and are listed to clarify things for users.
Please make sure to include a date if you add or modify entries, and include versions and other config info where relavent.
Issues of ALSA itself
- there is no way to enumerate devices. you can list what hardware your system has, but there is no way to make ALSA spit a list containing hw:0,0, default:0, and so on. You just have to know, until the code and docs get better. (2006-06-24)
- ALSA end user documentation is weak. (2006-06-24).
- aoss is far from perfect. Making older OSS apps work under ALSA is not really a priority for ALSA developers; they think that everyone should just move to ALSA apps. Unfortunately for end users, this is not always possible. artsdsp is known to work better for some applications; libjackasyn and esddsp might also work better for some apps. (2006-06-24).
- aoss does not play well with dmix (2006-06-24)
- aoss has no volume control either (2006-06-24)
- Dmix can't alter volume; unlike arts there is no way to mix several streams and alter their volumes against each other; if one app is playing too loud and another too soft, you are stuck. Many simple apps (like system console beepers) have no volume control at all, while others expect to use the hardware mixer controls. (2006-06-24).
- volume controls are not consistent. Master only applies to the two front speakers, not to center or sub or rear speakers, those need to be configured separately and for every input.
Issues of other sound software
- making jackd operated thru dmix or in any other fashion where it needs to share the sound hardware may be problematic. jackd is designed such that it really wants to own the hardware, which is reasonable for its intended users, professional audio people who need zero latency. If, however, you want to be able to hear an audio alarm go off while you happen to be editing a sound file (and not DJ'ing to a large crowd or mixing a band playing live), then you might have some problems. One offered suggestion on the alsa-users mailing list is that the dmix device by default is default:0; if you can force jackd to use it for output, you might be satisfied. (ALSA 1.0.11rc2), (2006-06-24).
Please move items here from above if an issue is known to have been fixed. This does not include wontfix or other "it's supposed to be that way" issues, only issues which everyone can agree have been fixed.
- there is no list in the user documentation of ALSA's problematic issues (2006-06-23).
- this FAQ page has been created. (2006-06-24).